[Sysadmins] Timing automated batch jobs ...

Mícheál Ó Foghlú mofoghlu at tssg.org
Fri Sep 18 10:11:38 IST 2009

Hi David,

That's funny!

I always thought of the Poisson as a good statistical way to simulate  
the arrivals of events to be processed in a simulation environment,  
not an operational one.
So it is an attempt to statistically re-create what (arguably) happens  
naturally when, for example, people arrive at a post office looking to  
conduct a transaction.
Thus I find it funny that it, in these special circumstances, it is  
being used operationally and not just for simulation.
I see that it is linked to when people do measurements.... ummm...  
must chat to you about this :-)


On 17 Sep 2009, at 20:46, David Malone wrote:

> On Tue, Sep 15, 2009 at 12:27:25PM +0100, Colm MacC?rthaigh wrote:
>> For some reason, I keep coming across the pattern of cron jobs that
>> have "sleep $RANDOM % 3600" in them - in a vain attempt to spread
>> load. It's a really harmful dangerous pattern, it annoyed me so much,
>> that I've written about it ;
> There is a pattern like this that is useful, which is to use a
> Poisson arrival process for a cron job. This is sometimes used when
> people do measurements, because it has some nice statistical
> properties (look for "PASTA" - Poisson Arrivals see Time Averages).
> This would look something like:
> 	sleep -3600*log($RANDOM/MAX_RANDOM)
> but would only be used in somewhat specialist circumstances. I think
> that RIPE TT boxes use this for doing their measurements.
> 	David.
> _______________________________________________
> Sysadmins mailing list
> Sysadmins at lists.stdlib.net
> http://lists.stdlib.net/mailman/listinfo/sysadmins

Micheal O Foghlu		     <Tel: +353 51 302963>
Executive Director Research	     <Mob: +353 86 8044640>
Telecommunications Software	     <Fax: +353 51 341100>
   & Systems Group		     <SIP: 0766030599 at blueface.ie>
ArcLabs Research & Innovation Centre <Email: mofoghlu at tssg.org>
West Campus			     <Skype: mofoghlu>
Waterford Institute of Technology    <Blog: http://www.ofoghlu.net/log>
Carriganore, Co. Waterford, Ireland  <Company: http://www.tssg.org>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.stdlib.net/pipermail/sysadmins/attachments/20090918/bebac75f/attachment.htm 

More information about the Sysadmins mailing list